Calla

It is a rhizomatous herbaceous perennial plant growing in bogs and ponds. The leaves are rounded to heart-shaped, long on a petiole, and broad. The greenish-yellow inflorescence is produced on a spadix about long, enclosed in a white spathe. The fruit is a cluster of red berries, each berry containing several seeds. The plant is very poisonous when fresh due to its high oxalic acid content, but the rhizome (like that of Caladium, Colocasia, and Arum) is edible after drying, grinding, leaching and boiling. == Taxonomy ==

The genus Calla and its sole species Calla palustris were first described by Carl Linnaeus in 1753. The genus formerly also included a number of other species, which have now been transferred to the separate genus Zantedeschia. These plants from tropical Africa, however, are still often termed "calla lilies" but should not be confused with C. palustris. The genus Calla has been regarded as a "puzzling case" in relation to its systematic position. Its pollen is unusual within the family Araceae. The pollen grains are small, ornamented differently, and with a differently constructed exine. Treatments based on anatomy and morphology have tended to separate Calla from other aroids.) Molecular phylogenetic studies on the other hand place Calla within the subfamily Aroideae, where it may be given its own tribe Calleae. == Distribution ==

It is native to cool temperate regions of the Northern Hemisphere, in central, eastern and northern Europe (France and Norway eastward, but not Britain), northern Asia and northern North America (Alaska, Canada, and northeastern contiguous United States). == References ==